Cardiovascular Autonomic Dysfunction in Patients with Cancer.

ABSTRACT

PURPOSE OF REVIEW Elucidating the mechanisms that contribute to adverse cardiovascular (CV) outcomes and reduce quality of life among patients with cancer is paramount. Cancer, certain cancer drugs, radiation therapy, cancer-associated lifestyle disturbances, and cancer-independent comorbidities combine to predispose oncology patients to autonomic dysfunction (AD). This review will explore the assessment, etiology, and clinical implications of AD in cancer patients and will speculate on therapeutic and research opportunities. RECENT FINDINGS: AD is particularly prevalent among patients with advanced cancer, but studies suggest increased prevalence across the entire continuum of cancer survivors compared to cancer-free controls. Data on cancer therapy-induced injury to the autonomic nervous system are limited to small studies. AD has been reported after cranial, neck, and mediastinal radiation therapy. Although AD has been shown to confer increased risk of adverse CV outcomes in cancer-free patients, the prognostic relevance of AD in oncology patients is less well investigated. Markers of AD including elevated resting heart rate (HR), reduced HR variability, and abnormal HR recovery have been associated with shorter survival times in various cancer cohorts. Furthermore, AD has been implicated in the etiology of cancer-related fatigue and exercise limitation. Multiple risk factors predispose oncology patients to AD, which is associated with adverse outcomes, including increased mortality, exercise limitation, and fatigue among this cohort. The contribution of AD to overall morbidity and mortality in cancer survivors has largely been overlooked to date. Further investigation is necessary to better understand cancer-treatment specific autonomic injury and to evaluate the role of various pharmacological and non-pharmacological interventions with potential to tackle the sympathovagal imbalance observed in cancer survivors.